ipc: fix fullscreen deco_rect
ipc: fix fullscreen deco_rect

This fixes the deco_rect reported by the ipc for fullscreen containers
to be all zeroes. Children of the fullscreen container should still
have their decorations reported correctly

SirCmpwn/sway,ascent12/sway,ascent12/sway,1ace/sway,1ace/sway,1ace/sway,ascent12/sway